1  /*
       2   * Copyright (C) 1999, 2001 by Andries Brouwer
       3   * Copyright (C) 1999, 2000, 2003 by Theodore Ts'o
       4   * Copyright (C) 2008 Karel Zak <kzak@redhat.com>
       5   *
       6   * This file may be redistributed under the terms of the
       7   * GNU Lesser General Public License.
       8   */
       9  
      10  #include <stdio.h>
      11  #include <stdlib.h>
      12  #include <unistd.h>
      13  #include <string.h>
      14  #include <errno.h>
      15  #include <ctype.h>
      16  #include <stdint.h>
      17  
      18  #include "superblocks.h"
      19  
      20  struct romfs_super_block {
      21  	unsigned char	ros_magic[8];
      22  	uint32_t	ros_full_size;
      23  	uint32_t	ros_checksum;
      24  	unsigned char	ros_volume[16];
      25  } __attribute__((packed));
      26  
      27  static int romfs_verify_csum(blkid_probe pr, const struct blkid_idmag *mag,
      28  		const struct romfs_super_block *ros)
      29  {
      30  	uint32_t csummed_size = min((uint32_t) 512,
      31  			be32_to_cpu(ros->ros_full_size));
      32  	unsigned char *csummed;
      33  	uint32_t csum;
      34  
      35  	if (csummed_size % sizeof(uint32_t) != 0)
      36  		return 0;
      37  
      38  	csummed = blkid_probe_get_sb_buffer(pr, mag, csummed_size);
      39  	if (!csummed)
      40  		return 0;
      41  
      42  	csum = 0;
      43  	while (csummed_size) {
      44  		csum += be32_to_cpu(*(uint32_t *) csummed);
      45  		csummed_size -= sizeof(uint32_t);
      46  		csummed += sizeof(uint32_t);
      47  	}
      48  	return blkid_probe_verify_csum(pr, csum, 0);
      49  }
      50  
      51  static int probe_romfs(blkid_probe pr, const struct blkid_idmag *mag)
      52  {
      53  	struct romfs_super_block *ros;
      54  
      55  	ros = blkid_probe_get_sb(pr, mag, struct romfs_super_block);
      56  	if (!ros)
      57  		return errno ? -errno : 1;
      58  
      59  	if (!romfs_verify_csum(pr, mag, ros))
      60  		return 1;
      61  
      62  	if (*((char *) ros->ros_volume) != '\0')
      63  		blkid_probe_set_label(pr, ros->ros_volume,
      64  				sizeof(ros->ros_volume));
      65  
      66  	blkid_probe_set_fsblocksize(pr, 1024);
      67  	blkid_probe_set_fssize(pr, be32_to_cpu(ros->ros_full_size));
      68  	blkid_probe_set_block_size(pr, 1024);
      69  
      70  	return 0;
      71  }
      72  
      73  const struct blkid_idinfo romfs_idinfo =
      74  {
      75  	.name		= "romfs",
      76  	.usage		= BLKID_USAGE_FILESYSTEM,
      77  	.probefunc	= probe_romfs,
      78  	.magics		=
      79  	{
      80  		{ .magic = "-rom1fs-", .len = 8 },
      81  		{ NULL }
      82  	}
      83  };
      84